Dynamo-electric machine



1 3 P. l. CHANDEYSSON DYNAMO ELECTRIC MACHINE Filed Aug. 3, 1931 I 2 Sheets-Sheet l 1933- P. I. CHANDEYSSON 1,922,023

DYN-AMO ELECTRIC MACHINE Filed Aug. 3. 1931. 2 Sheets-Sheet 2 IDIEARE/ ['mlvaevsswg yrxm 1%. A

Patented Aug. 15, 1933 UNITED STATES PATENT OFFICE 18 Claims.

This invention pertains to dynamo-electric machines, and more particularly to machines of the homopolar type.

One of the objects of this invention is to provide a machine of this type of simple construction which will be capable of handling a large current at a low voltage.

Another object of this invention is to provide a construction for a machine of this type which will be economical to manufacture in all sizes of machines.

Another object is to provide a construction which will avoid undue loss of energy in the operation of the machines.

Another object of this invention is to provide novel and improved current-collecting devices for such a machine.

Another object is to provide improved means for cooling the machine.

Further objects will appear from the following description when taken in connection with the accompanying drawings, in which:

Figure 1 is a longitudinal vertical section of a machine embodying this invention;

Figure 2 is a section on line 2-2 of Figure 1;

Figure 3 is a view similar to Figure'l showing another embodiment of this invention;

Figure 4 is a view similar to Figure 3, but showing only the field-frame in section and other parts in elevation; and

Figure 5 is a detail of the brush holder construction.

Referring to the drawings, 1 designates a base 7 of any suitable construction upon which the machine is mounted. Journaled in bearings 2 and mounted upon, but insulated from the base 1, is a rotor 3. This may beTzrovided with a; pulley 4, or other suitable means for driving the rotor in rotation.

The rotor 3 is constructed of magnetic material of any suitable type preferably a material of high magnetic permeability. For instance, the rotor 3 may be constructed of iron or steel. It is generally cylindric in form and may be provided on its peripheral surface with a coating 5 of a material of good electrical conductivity, such as copper. The coating 5 may be applied in a simple manner by plating on the cylindric surface and preferably a heavy coating is applied. .Such a coating not only provides a skin of high conductivity for the rotor, but provides a good contact surface for the current-collecting devices so that the losses of energy due to contact resistance may be reduced to a minimum. Other materials besides copper, which are good conductors electrically and thermally may, of course, be employed for this coating. Such coating, particularly of copper, renders the surface less liable to be burned or pitted by sparking at the brushes.

Surrounding the rotor 3 is a series of rings 6 of magnetic material, such as iron. These rings are arranged to clear the rotor with a suitable air gap 7. In the embodiment illustrated there are four of these rings 6. Arranged to surround and support the rings 6 is a field-frame structure. This structure is built in two separate parts each comprising a main core portion 8 and a yoke portion 9. The core portions 8 are provided with an inner circular bore closely fitted to the outer circumference of the rings 6. The outer perimeter of the core portions 8 may be rectangular as shown in Figure 2, or they may be circular, polygonal, or of any-other suitable shape.

The rings 6 are arranged in pairs spaced along the rotor 3, as shown in Figure 1, and the core portions 8 are spaced accordingly. The outer edge of each pair of core portions 8 is bridged by one of the yoke portions 9 as will be clearly seen from Figure 1. Thus each pair of rings 6 with its core portions 8 and yoke portions 9 forms one part of the field-frame structure of which two are shown placed side by side in Figure 1- and insulated from each other by an insulating plate 10 of any suitable material. The field-frame is also supported on the base 1, but is insulated therefrom by suitable insulation 11.

The core portions 8 and the yoke portions 9 are permanently secured tpgether to form the field-frame structure, but the entire structure is split diametrically as indicated at 12 so that the same may be assembled around the rotor. The rings 6 are not permanently secured to the core portions 8, but are continuous around the rotor- .and are fitted to said core portions. Accordingly if the upper half of the field-frame structure be lifted off, the rings 6 will be separated from the rest of the structure and remain in place on therotor.

The rings 6 are somewhat wider than the core portions 8 so that they project inwardly thereof. Mounted on the inner projections of these rings are field exciting coils 13. These coils are wound i n'ring form and completely insulated before being assembled in the machine. Their terminal wires 14 may be brought out through suitable insulating bushings at the split portion 12 of the field-frame as shown in Figure 2. These field coils may be wound for any suitable voltage and may be energized from a separate source of power, or if designed for the same voltage, may be energized from the terminals of the machine itself.

Current collecting devices are mounted within each of the field-frame parts and between the rings 6. These rings may be slotted to receive a series of spacing or supporting bars 15. These bars extend across the space. between each pair of rings 6 so as to provide therebetween a series of pockets adapted to receive suitable brushes 16. In the embodiment illustrated in the drawings a plurality of brushes 16 is movably mounted between each pair of bars 15 and so as to engage the surface of the rotor 3 between the rings 6. These brushes act to collect current from the rotor. Each brush may be electrically connected to one of the bars 15 by a suitable fiexible conductor 17. The bars 15 are not insulated from the rings 6, but are in electrical contact therewith and may even be soldered thereto.

Any suitable means for maintaining the brushes 16 in firm contact with the rotor may be provided. In the embodiment illustrated in Figure 4, since the field-frame structure forms a complete enclosing casing around the collecting devices, an air inlet 18 may be formed in that casing and connected to a suitable air supply pipe 19 so that pneumatic pressure may be established within the casing. This pressure acts upon the outer ends of all the brushes 16 tending to force them against the surface of the rotor 3. As these brushes must fit somewhat loosely in their sockets in order to permit movement thereof under this pressure, a quantity of air will continually leak past the brushes and into the air gap 7. This air passes out of the air gap at the ends of the rotor. The continual passage of such air assists in cooling the rotor so as to prevent undue heating thereof.

The operation of this machine is in accordance with well known principles. The field coils 13 being energized establish a magnetic field traversing the field-frame and the rotor as indicated by the arrows in Figure 1. The core portions 8 and the yoke portion 9 form part of the magnetic circuit while the rings 6 provide pole shoes serving to distribute the magnetic field along the rotor. The rotation of the rotor in this field generates an electromotive force which causes currents to pass along the rotor from one set of brushes 16 to the other. These brushes contacting with the surface of the rotor and being connected through the bars 15 to the rings 6, establish an electrical circuit from the rotor to the field-frame. It will be noted that an electrical circuit is established from one field-frame part through the rotor to the other field-frame part. Accordingly these frame parts may provide circuit terminals for the machine. Connection may be made to these field-frame terminals in a convenient manner by providing connecting strips or terminals 20 in the form of fiat copper strips placed between the field-frame and the support 1, but insulated from the latter as shown in Figure 1. These conducting strips 20 are securely fixedin any suitable manner to the field-frame so that the current may be delivered to the outer circuit by means of these conductors or terminals. The terminals 20 may, of course, be connected directly to the rings 6.

In the embodiment shown in Figures 3 and 4 that part of the field frame structure including core portions 8 and yoke portions 9 is shown as constructed of a single casting instead of being built up of a plurality of relatively thick flat plates as indicated in Figures 1 and 2. These two structures act alike in the operation of a machine. However, the construction of Figure 1 has the advantage of greatly reduced cost over the other structure.

In building up the field-frame structures of Figures 1 and 2 iron or steel plates of about the thickness of ordinary boiler plate are assembled. in sufficient numbers to build up these parts. The core portions 8 may have their circular bore cut out by means of an acetylene torch and after assembly this bore may be accurately machined to t the rings 6. This is a simple and cheap method of manufacture and shows a marked economy over the structure by castings as shown in Figures 3 and 4..

Where these plates are described in the appended claims as relatively thick plates, the designation is intended to indicate plates of about the thickness of boiler plates which are thick enough to be stiff in large sheets and yet thin enough to be handled by sheet handling methods rather than as blocks.

It has been found that a machine constructed in accordance with this invention is capable of delivering a very large current at a low voltage and at a relatively high efiiciency.

The mechanical structure is such as to render the assembly of a machine of this type a simple matter even in the case of large machines where the parts are very heavy. The assembly is carried out by first mounting the lower halves of the field-frame parts on the base 1 in their proper positions. The rotor is then suitably supported and the rings 6 together with the brush-holder structure are slipped onto the rotor. The field coils 13 are also assembled on the rotor over the rings 6. With these parts so assembled the rotor may then be swung from a crane and deposited in the bearings 2. During this operation the rings 6 are properly fitted in the lower half of the core portions 8. This is a simple matter since all of these parts are easily accessible during the operation. The upper halves of the field-frame parts may now be placed on the machine. The upper and lower halves may be provided with suitable flanges 21 which are then bolted together so as to secure the upper halves.

It will be seen that this invention provides a homopolar dynamo electric machine of simple construction and one which is cheap to manufacture. The arrangement of the main circuit from one field-frame part through the rotor to the other field-frame part provides great simplicity in manufacture and operation. It will be noted that no insulation is used in the machine except the plate 10 between the two frame parts and the insulation 11 at the base. The copper coating on the rotor provides ample conductivity forcarrying the currents in the rotor and also a low resistance contact surface for the brushes.

' Obviously these machines are reversible and both motors and generators may be built in accordance with this invention.

While the invention has been described as a unitary machine, it will be understood that individual features or sub-combinations thereof may be useful without reference to other features. It is understood that the employment of such individual features or sub-combinations is contemplated by this invention and is within the scope of the appended claims.

It is further obvious, therefore, that various changes may be made, within the scope of the appended claims, in the details of construction without departing from the spirit of this invention; it is to be understood, therefore, that this invention is not limited to the specific details shown and/or described.

' Having thus described the invention, what is claimed is:

1. A dynamo-electric machine of the character described, comprising, a field-frame structure in two parts insulated from each other, a rotor mounted for rotation in said field-frame structure, and means establishing an electric circuit from one of said frame parts, thru said rotor to the other of said frame ,parts.

2. A dynamo-electric machine of the character described, comprising, a field-frame structure in two parts insulated from each other, a rotor mounted for rotation in said field-frame structure, and collector means engaging said rotor adapted to establish an electric circuit from one of said frame parts, thru said rotor to the other of said frame parts.

3. A dynamo-electric machine of the character described, comprising, a field-frame structure in two parts insulated from each other, a rotor mounted for rotation in said field-frame structure, means establishing an electric circuit from one of said frame parts, thru said rotor to the other of said frame parts, and circuit terminals attached to said frame parts.

4. A dynamo-electric machine of the character described, comprising, a field-frame structure in two parts insulated from each other, a rotor mounted for rotation in said field-frame structure, means establishing an electric circuit from one of said frame parts, thru said rotor to the other of said frame parts, and circuit terminals beneath and supporting said frame structure.

5. A dynamo-electric machine of the character described, comprising, a field-frame structure divided longitudinally thereof, a rotor mounted for rotation therein, and a separate continuous ring surrounding said rotor and fitted to said fieldframe structure to be secured therein by assembly of said structure adapted to provide a pole shoe therefor.

6. A dynamo-electric machine of the character described, comprising, a field-frame structure divided longitudinally thereof, a rotor mounted for rotation therein, a separate continuous ring surrounding said rotor and fitted to said fieldframe structure to be secured therein by assembly of said structure adapted to provide a pole shoe therefor, and a field exciting coil mounted on said ring. I

7 A dynamo-electric machine of the character described, comprising, a field-frame structure divided longitudinally thereof, a rotor mounted for rotation therein, a separate continuous ring surrounding said rotor and fitted to said fieldframe structure to be secured therein by assembly of said structure adapted to provide a pole shoe projecting inwardly of said frame, and a field exciting coil mounted on the inner projection of said ring.

8. A dynamo-electric machine of the character described, comprising, a field-frame structure in two parts insulated from each other, a rotor mounted for rotation in said field-frame structure, and a separate continuous pole-shoe ring surrounding said rotor, said frame structure being split diametrically and fitted to said ring.

9. A dynamo-electric machine of the character described, comprising, a field-frame structure in two parts insulated from each other, a rotor mounted for rotation in said field-frame struc ture, a separate continuous pole-shoe ring surrounding said rotor, said frame structure'being split diametrically and fitted to said ring, and a field exciting coil mounted on said ring.

10. In a direct current dynamo-electric machine of the character described, a field frame structure comprising, a pole shoe, a main core portion abutting said shoe, and a yoke portion abutting said core portion, said core and yoke portions being built up of a series of relatively thick flat plates.

11. In a direct current dynamo-electric machine of the character described having a fieldframe structure and a rotor mounted for rotation therein, a main core portion and a yoke portion for said field-frame built up of relatively thick flat plates.

12. In a direct current dynamo-electric machine of the character described, having a field-frame structure and a rotor mounted for rotation therein, a main core portion built up of relatively thick plates positioned radially of said rotor, a yoke portion similarly built up of relatively thick fiat plates abutting said core portion, and a continuous pole shoe fitted to said core portion.

13. A dynamo-electric machine of the character described, comprising, a field-frame structure, a rotor mounted for rotation therein, and current-collecting means engaging said rotor and mounted on and in electrical contact with said field-frame.

14. A dynamo-electric machine of the character described, comprising, a field-frame structure, a rotor mounted for rotation therein, a pole shoe for said field-frame embracing said rotor, and a current-collecting device mounted on said pole shoe and electrically connected therewith and engaging. said rotor. i

15. A dynamo-electric machine of the character described, comprising, a field-frame structure, a rotor mounted for rotation therein, and currentcollecting means engaging said rotor, said frame structure including a casing enclosing said collecting means adapted to receive pneumatic pressure to be applied to said collecting means.

16. A dynamo-electric machine of the character described, comprising, a field-frame structure, a

conductivity on the peripheral surface thereof,

and brushes bearing on said coating.

PIERRE I. CHANDEYSSO N. 

